In relation to animal farming, in particular furred animal farming such as mink farming, the animals are typically kept in a building or shed in which the animals are accommodated either in individual cages, or with a small number of animals in each cage. The word “cage” should be understood to encompass also similar enclosures for animals. The building typically has a roof and walls, however, it may also have an at least partially open structure. The cages are typically positioned on each side of a passage through the building. In small farms the animals may be fed manually; however, in larger farms, the feeding of the animals is performed by using a motorized feeding vehicle.
The motorized feeding vehicle may comprise a chassis, a driver position, a movement control system, a power system, a steering system and an animal feeding system. The feeding system comprises a feed storage tank and a pipe for delivering the animal feed directly on the cages. The feed is typically provided in a flowable form. The user thus drives into the building and adjacent a cage such that the pipe is located above the cage and then operates a pump or delivery system for delivering a user determined amount of feed for the individual animal.
The operation of such motorized feeding vehicles is very monotonous work since it involves driving to a cage, operating the feeding system, driving to the next cage, and so on. Further, the feeding must be repeated several times every day at the times when the animals should be fed. Thus, in the prior art there has been committed significant work for developing technologies for allowing the motorized feeding vehicle to be automatically controlled. Some of the prior art technologies are described below:    The German patent application DE 10 2006 037 232 A1 describes a navigation system for a vehicle which has an internal wireless reader which may read location data from transponders positioned in the same area as the vehicle.    The Danish patent DK 176 402 B1 describes a fully automatic feeding vehicle, which may move automatically along a predetermined path by the aid of a wireless positioning system, such as a GPS system.    The Danish patent DK 177 425 B1 describes a feeding vehicle having a navigation system, which measures the angular rotation of a wheel and calculates the distance which the feeding vehicle has moved based on the radius and the angular movement of the wheel.    The Danish patent DK 177 406 B1 describes a feeding vehicle having a feeding pipe divided into two pipe sections and a servo motor for moving the feeding pipe.    The European patent application EP 366 350 A2 describes a vehicle for primarily unmanned operation equipped with an upwardly pointing video camera which during a manually driven learning mode observes overhead features which during a subsequent unmanned trip are used for guidance.    The Dutch patent NL 1020093 relates to an autonomous vehicle having a detector for detecting floor markings.    The Dutch patent NL 1035687 relates to an unmanned vehicle having a control system using sensors or GPS. The sensors of the control system may be slides or land-marks in the surroundings in which the vehicle is used.    The United Stated patent application US 2010/0161225 A1 relates to a method of building map information using a 3D camera for localization.    The international patent application WO 2008/101500 A1 relates to a system for feeding fur animals in which an unmanned motorized feed cart is guided along a guide wire. The document also describes the use of RFID tags.    The European patent EP 2 124 528 B1 relates to an unmanned vehicle for supplying feed to an animal and having a sensor for forming an image of an observation area.    The Chinese utility model CN 203015614 U describes an automatic feeding machine for fur-bearing animals having a feed hopper and a feed pump.    The Chinese utility model CN 202697443 U describes an automatic feeding machine comprising a seat and a steering wheel.    The Chinese utility model CN 201426302 Y describes an automatic feeding machine comprising a hydraulic motor and a hydraulic pump.    The Chinese utility model CN 201690880 U describes an automatic feeding machine having a hopper and a feed conveying device.    The Chinese utility model CN 2017337000 relates to a small sized three wheeled vehicle having a handlebar type steering device.    The Chinese application CN 103004626A relates to a machine for distributing feeding meat to animals having a power device that is fixedly connected to a gear shaft provided with a meshed gear pump and discharging pipe that is connected with the bottom of a storage hopper arranged with a feeding port.    The European patent EP 0 739 161 B1 relates to a feed wagon moving between feed loading stations by means of a detection device for the detection of passive beacons or a wire.    The European patent EP 2 334 169 B1 relates to an unmanned vehicle having a protective device in the form of an electrical conductor for protecting the vehicle against obstacles such as animal legs.    The U.S. Pat. No. 7,689,434 B1 relates to an animal feeding system comprising a vehicle having a GPS system.    The U.S. Pat. No. 5,424,957 relates to a control and monitoring system mount in a feed truck which detects whether feed remains in the bunks from prior feedings.    The Danish patent 176 138 B1 relates to a method of increasing the fertility of female animals by automatic individual feeding of the animals.    GB 1 564 197 relates to a fodder distribution system comprising a row of individual troughs and a fodder distribution vehicle which is movable along the row.    US 2007/0288249 relates to a system comprising at least one device for measuring one or more parameters of individual animals, the data being used to determine management strategies for individual animals in real-time.
The automatic feeding vehicles mentioned in the above mentioned documents allow for an automatic feeding of caged animals without the direct involvement of a user. In order to allow the feeding vehicle to navigate without the need of user involvement, it is necessary for the feeding vehicle to comprise a navigation system. The navigation systems used in the above mentioned prior art documents may basically be divided into global navigation systems, such as GPS, local navigation systems, such as RFID tags or cameras; and onboard navigation systems, such as an onboard distance and directional measurement.
All of the above systems have their individual advantages and drawbacks. The global navigation systems typically depend on satellites emitting high frequency radio waves which allow a very accurate localization but which cannot be accurately received indoors. Local navigation systems may be positioned both indoors and outdoors; however, they may be very sensitive to dust, rain, snow, and similar environmental influence. Onboard navigation systems have the inherent drawback that a well determined starting position is required, and any navigation error thereafter is cumulative and thus increases over time and distance from the well-defined starting point.
Some navigation systems depend on beacons or electric wires which are installed on the premises of the animal farming system. Such navigation systems may provide a high location accuracy by utilizing a method such as triangulation for position; however, such systems require high investments to be made in order to install the system. There is, however, a need for accurate location systems which may be used directly in an existing animal farming system without having to invest in new infrastructure.
Thus, all of the above described feeding vehicles suffer from a risk of failure in the navigation system. Such failure should be avoided since it will require user involvement. Therefore, the object of the present invention is to find a technology which allows for a more secure and fail-safe navigation of a motorized feeding vehicle while keeping the investment in the animal farming system low.